Reference: Sha’baan 1417AH
ad-Durar an-Naadhirah fil-Fataawa al-Mu’aasirah – Page 486
Question: If a man is impotent, is it permissible for him to get married without mentioning this defect, as he has been advised that this problem will pass after marriage?
And is it permissible for him to use medical stimulants (i.e. viagra)?
Response: It is permissible for him to get married so long as he makes mention of this defect before the [marriage] contract, and it is not permissible for him to remain quiet about it because this is from cheating and deception and tadlees (making out he is capable whilst he is not). And if there is a permissible remedy for this problem which he can benefit from, then he should use it.